ICAL  INSTRUCTION    IN 
A  FASCINATING  ART 


FIFTY  CENTS 


POPULAR  MECHANICS  HANDBOOKS 


UNIVERSITY  OF  CALIFORNIA 
AT    LOS  ANGELES 


UMVERSriTofCALIFORNM 

AT 

LOS  ANGELES 
LIBRARY 


Metal  Spinning 

BY 

Prof.  FRED  D.  CRAWSHAW,  M.  E., 

Assistant  Dean, 
College  of  Engineering,  University  of  Illino'u 


POPULAR  MECHANICS  HANDBOOKS 


CHICAGO 
POPULAR   MECHANICS  CO. 


Copyrighted,  1909, 
By  H.  H.  WINDSOR 


1 

^0  (e 


THIS  book  is  one  of  the  series  of 
handbooks    on  industrial    subjects 
being  published    by  the  Popular 
Mechanics  Co.  Like  the  magazine,  these 
books  are  "written  so  you  can  under- 
stand  it,"  and  are  intended  to  furnish 
information  on  mechanical  subjects  at  a 
price  within  the  reach  of  all. 

The  texts  and  illustrations  have  been 
prepared  expressly  for  this  Handbook 
Series,  by  experts;  are  up-to-date,  and 
have  been  revised  by  the  editor  of  Pop- 
ular Mechanics. 


Fig.  1 — Lathe  for  Metal  Spinning 


Chapters 

The  Lathe  and  Its  Parts  .  .  Chapter  I 

Tools Chapter  II 

The  Preparation  of  Metal  for  Spinning 

' Chapter  III 

How  to  Spin  a  Hollow  Dish  .  Chapter  IV 

How  to  Spin  a  Deep  Dish  .  Chapter  V 

How  to  Spin  a  Vase  .  .  .  Chapter  VI 
How  to  Spin  Some  Unclassified  Forms 

Chapter  VII 


METAL  SPINNING 


INTRODUCTION 

Sheet  metal,  which  is'  now  pressed  and  stamped  into  a  great  va- 
riety of  forms  for  commercial  uses,  was,  up  to  a  few  years  ago,  either 
hammered  or  spun  into  the  desired  shapes  by  a  comparatively 
few  artisans  who  had  learned  the  art  of  cold-metal  working  in 
Europe.  Like  so  many  other  of  the  old-time  crafts,  the  one  of 
metal  spinning  has  partially  come  into  disuse  because  of  commer- 
cial competition  and  the  failure  of  the  younger  generation  of  men 
to  familiarize  themselves  with  the  handwork  of  their  fathers.  In 
the  United  States,  it  is  only  in  the  larger  cities  that  one  occa- 
sionally finds  an  artisan  who  does  metal  spinning;  when  such  a 
person  is  found,  he  is  usually  occupied  in  producing  forms  out 
of  thin  metal  that  require  great  care  in  making  or  are  difficult 
to  produce  with  a  stamp  or  press.  Sometimes,  however,  where 
only  a  comparatively  few  articles  of  any  particular  shape  are 
desired,  they  are  spun  instead  of  stamped  out,  to  save  the  cost 
of  dies. 

It  is  believed  in  some  quarters,  particularly  among  metal 
spinners,  that  pressing  and  stamping  metal  can  never  fully  take 
the  place  of  spinning  it.  It  is  impossible  to  press  or  stamp  some 
forms  except  as  they  are  produced  in  parts  and  these  parts  sol- 
dered, brazed  or  riveted  together.  This  is  manifestly  undesir- 
able for  many  kinds  of  work. 


10  METAL  SPINNING 

The  fact  that  modern  commercial  tendencies  are  in  the  direc- 
tion of  abolishing  metal  spinning  wherever  possible  does  not 
mean  that  large  sheet-metal  working  establishments  do  not  em- 
ploy metal  spinners;  it  does  mean,  however,  that  these  men  are 
called  upon  to  do  the  hardest  kind  of  spinning  without  much 
possibility  of  learning  how  to  do  the  simpler  forms  of  this  work. 

It  is  for  the  double  purpose,  therefore,  of  making  it  possible 
for  amateurs  to  be  helped  in  me\a»  spinning  and  to  renew  this 
craft  where  metal  spinning  is  really  more  serviceable  than  its 
substitutes,  that  this  book  is  written. 

From  the  standpoint  of  the  craftsman,  metal  spinning  is  a 
craft  which  is  highly  desirable  of  attainment  and  which  may 
replace  beaten-metal  work  in  some  cases,  or,  in  many  cases  be 
used  in  connection  with  it.  The  principal  field  of  the  metal 
spinner,  however,  is  the  production  of  forms  for  plated  ware. 
Practically  all  silver  plate  has  white  metal,  which  has  been  pressed 
or  spun  into  shape,  as  a  base.  There  are  also  many  forms  used 
in  connection  with  manufactured  articles,  notably  electric  fix- 
tures, which  can  be,  and  many  times  are,  spun  with  greater 
certainty  of  good  results  than  could  be  possible  if  other  methods 
are  used. 

For  those  who  take  up  this  work  for  the  first  time,  it  is  sug- 
gested that  forms  be  undertaken  after  the  order  of  those  de- 
scribed in  the  following  chapters  and  that  copper  well  annealed 
be  used  as  the  practice  metal. 

FRED  D.  CRAWSHAW 


CHAPTER  I 

THE  LATHE  AND  ITS  PARTS 

Metal  spinning  does  not  take  a  particularly  prom- 
inent place  among  the  trades  in  the  United  States. 
Inasmuch  as  it  is  perfectly  possible  to  spin  metal  on 
an  engine  lathe  or  a  speed  lathe,  if  either  is  properly 
equipped  for  this  work,  few  manufacturers  of  ma- 
chine tools  make  a  lathe  specially  for  spinning. 
The  work  requires  a  lathe  which  will  not  move  side- 
wise  to  any  great  extent  as  a  result  of  heavy  work 
running  at  a  high  speed.  The  ordinary  engine  lathe 
does  not  fulfil  the  requirements  of  speed;  on  the 
other  hand  the  speed  lathe,  unless  it  is  designed  for 
heavy  work,  is  liable  to  be  unstable. 

The  frontispiece,  Fig.  1,  illustrates  a  strong 
speed  lathe  equipped  for  metal  spinning.  It  will  be 
noticed  that  the  legs  of  the  lathe  are  particularly 
well  braced  and  that  the  entire  machine  presents 
the  appearance  of  strength.  Inasmuch  as  the  writer 
has  worked  upon  a  lathe  similar  to  the  one  illus- 
trated and  has  spun  different  kinds  of  metal  of  vary- 
ing disk  diameters  on  it  without  inconvenience 
from  lathe  vibration,  he  feels  that  he  can  safely 
recommend  a  strong  speed  lathe  for  ordinary  metal 
spinning  work. 

The  principal  lathe  requirement  for  good  spin- 
ning is  a  speed  ranging  from  1,800  r.p.m.  to  2,500 
r.p.m.,  which  can  be  maintained  with  but  slight 
variation  whether  light  or  heavy  spinning  is  being 
done.  The  length  of  the  spinning  tools  and  the 
method  of  holding  them  produce  a  firm  contact  be- 


12 

(VI 
6 

lL 

METAL  SPINNING 

<       «o 

\ 

z 
a 

O 

o 

O 
0 

© 

o 
o 
o 

0 

1" 

~\r 

.SPINNERS  REST 

METAL  SPINNING  13 

tween  the  tool  and  the  metal,  and  this  requires  a 
lathe  which  has  in  store  a  considerable  amount  of 
reserve  power.  For  ordinary  work,  a  spinner 
should  use  at  least  a  half-horsepower  lathe,  but  for 
work  in  schools  or  light  work  in  shops,  good  results 
can  be  obtained  with  a  quarter-horsepower  lathe 
which  has  a  large  head  cone  and  is  strongly  belted. 

The  parts  of  the  lathe,  when  equipped  for  metal 
spinning,  which  differ  from  corresponding  parts 
when  the  lathe  is  used  for  metal  turning,  are  the 
headstock,  faceplate,  tool-rest  and  tail  center.  The 
dog  which  is  so  commonly  used  in  the  metal  work- 
ing shop  to  hold  work  from  slipping  in  the  lathe  as 
it  revolves  is  never  used  in  metal  spinning.  The 
ordinary  center  screw  faceplate  or  outside  screw 
faceplate  used  in  wood-turning  is  screwed  onto  the 
headstock  spindle.  Upon  the  faceplate  is  screwed 
a  block  of  hard  wood,  usually  hard  maple ;  this  is 
turned  with  wood-turning  tools  to  the  shape  de- 
sired for  the  first  form  in  the  process  of  spinning. 
The  circular  disk  of  metal  which  is  to  be  spun  is 
centrally  placed  against  this  turned  form  and  held 
in  place  by  the  tail  center  which  is  brought  in  con- 
tact with  it.  Prior  to  the  time  when  spinning  be- 
gins, the  circular  disk  of  metal  is  held  in  place  by 
friction  between  the  wooden  form  fastened  to  the 
faceplate,  over  which  the  metal  is  to  be  spun,  and  the 
tail  center.  The  process  of  spinning  will  be  de- 
scribed later. 

The  lathe  rest  commonly  used  is  shown  in  Fig.  2. 
A  and  B  are  both  pieces  of  wrought  iron  which 
have  been  fastened  together  by  turning  a  shoulder 
on  the  upper  end  of  B  and  fitting  the  part  thus  made 
into  a  hole  bored  in  the  middle  of  A  and  counter- 


14 


METAL  SPINNING 


METAL  SPINNING  15 

sunk  at  the  top.  The  two  pieces  are  securely  fas- 
tened together  by  riveting  the  end  of  B  into  the 
countersunk  part  of  A.  This  simple  "T"-rest  is 
fastened  into  the  slide-rest  of  the  lathe.  It  replaces 
the  tool-rest  in  the  wood  lathe  equipment.  Now, 
as  will  be  explained  in  a  succeeding  chapter,  the 
plying  of  the  tool  over  the  disk  of  metal,  to  press 
it  securely  over  the  turned  form,  requires  the 
spinning  tool  to  act  as  a  lever.  The  direction 
of  motion  of  the  lever  varies  from  a  vertical  plane 
at  the  beginning  of  operations  to  a  horizontal  plane 
at  the  completion  of  the  spinning  process.  In  order 
that  this  may  be  done  without  the  tool  slipping  on 
the  rest,  vertical  holes  are  bored  about  %  in.  to  1  in. 
apart  in  the  horizontal  portion  of  the  rest  in  which 
is  inserted  a  movable  pin.  The  position  of  the  tool 
on  the  rest  is  shown  in  the  illustration,  Fig.  3.  As 
the  metal  is  gradually  pressed  over  the  form  the 
pin  is  moved  toward  the  headstock  of  the  lathe  by 
changing  it  from  one  hole  to  another.  For  small 
work  the  horizontal  portion  of  the  "T"-rest  can  be 
made  out  of  %-in.  or  %-in.  square  stock.  A  %-in. 
rod  will  answer  the  purpose  for  the  rest-pin.  The 
pin  should  be  shouldered  squarely  at  the  bottom  to 
fit  into  Vt-in.  holes  bored  in  the  rest. 

The  size  of  the  vertical  portion  of  the  "T"-rest 
will  depend  upon  the  hole  in  the  slide-rest  which 
receives  it.  I  am  assuming,  in  this  description,  that 
an  ordinary  speed  lathe  is  remodeled  to  serve  for 
spinning  purposes.  Some  difficulty  may  be  found 
in  the  rest  slipping  when  considerable  pressure  is 
used  in  the  spinning  process.  This  might  be 
avoided  by  using  a  "T"  or  square  pin  joint  to  fasten 


16 


METAL  SPINNING 


METAL  SPINNING  17 

the  two  parts  of  the  rest  together.  However,  if  the 
operator  will  shift  the  lathe  carriage  from  time  to 
time  to  keep  the  fulcrum  point  as  nearly  as  possible 
over  the  central  portion  of  the  rest,  little  difficulty 
will  be  experienced  in  this  direction. 

In  describing  the  spinner's  center  I  shall  illus- 
trate and  refer  to  three.  All  of  these  are  shown  in 
Fig.  4.  The  one  at  the  top  is  to  be  found  in  the 
market.  The  one  in  the  center  of  the  illustration 
is  described  because  a  practical  spinner,  after  years 
of  experience  and  after  using  many  forms  of 
centers,  finally  concluded  that  this  one  filled  all  re- 
quirements better  than  any  other  he  had  ever  seen 
or  used. 

Two  things  are  absolutely  necessary  in  any  cen- 
ter wrhich  is  used  in  metal  spinning.  The  first :  light 
contact  must  be  kept  between  the  end  of  the 
center  and  the  surface  of  the  metal  being  spun.  In 
other  words,  there  must  be  absolutely  no  slipping 
at  this  point.  The  second :  this  portion  of  the 
center  which  sticks,  as  it  were,  to  the  spinning 
metal  should  move  freely  and  without  much,  if  any, 
wear  on  the  remainder  of  the  center  which  is  in- 
serted in  the  tailstock.  In  order  to  have  these  two 
essential  factors  present  in  spinners'  centers  many 
devices  have  been  constructed.  Different  spinners 
use  different  centers,  often  devices  of  their  own ; 
but  experience  has  shown  that  the  two  centers  here 
described  have  worked  well — I  do  not  say  perfectly. 
The  center  illustrated  at  the  bottom  of  Fig.  4  is  one 
which  the  writer  tried  as  a  result  of  some  trouble 
which  he  had  with  the  top  center  shown  in  Fig.  4, 
and  before  he  used  the  one  shown  in  the  center  of 


18  METAL  SPINNING 

this  illustration.  It  has  the  advantage  of  having 
but  one  moving  metal  part,  which  serves  a  good  pur- 
pose in  some  respects,  viz,  it  reduces  to  a  mini- 
mum the  trouble  due  to  many  parts.  On  the  whole, 
the  middle  center  shown  in  Fig.  4  proves  the  most 
satisfactory. 

The  stock  center  is  made  in  three  parts — A,  B  and 
C.  A  and  C  are  cast-iron  parts  and  B  is  a  washer 
made  of  some  hard  substance  such  as  hard  rubber 
or  vulcanized  fiber,  against  which  cast-iron'  will  run 
freely.  B  is  supposed  to  fit  tightly  upon  the  pin  of 
C  so  that  A  alone  revolves  when  the  center  is  firmly 
pressed  against  the  disk  of  mecal  to  be  spun.  A 
may  be  made  in  different  shapes  to  accommodate 
different  forms  and  sizes  in  spinning  and  should  be 
lubricated  by  occasionally  dropping  oil  upon  the  pin 
of  C.  This  pin  should  not  enter  A  farther  than  is 
necessary  to  form  a  good  bearing,  and  should  fit 
about  as  tightly  in  A  as  a  shaft  in  a  high-grade  ma- 
chine fits  in  its  bearing.  The  one  difficulty  which 
the  writer  has  had  with  this  center,  as  well  as  with 
the  second  center  described,  is  the  impossibility  of 
making  the  diameter  of  A  small  enough  for  some 
work.  This  may  not  be  considered  an  objection  in 
the  trade  work,  but  in  schools,  where  small  pieces 
will  naturally  be  spun  more  than  large  ones,  it 
sometimes  forms  a  serious  drawback  to  accomplish- 
ing good  results.  The  center  shown  at  the  bottom 
of  Fig.  4  was  found  to  overcome  this  difficulty  be- 
cause the  revolving  part  of  the  center  can  be  turned 
as  small  as  one  desires.  Here,  however,  it  should 
be  mentioned  that,  if  the  end  bearing  surface  in  con- 
tact with  the  work  is  made  too  small,  a  perfect 


METAL  SPINNING  19 

contact  between  the  tail  center  and  the  work  cannot 
be  secured  and  a  very  undesirable  slipping-  will 
occur.  It  is  true,  nevertheless,  that  small  work  re- 
quires slight  pressure  from  the  tool,  and,  as  a  result, 
less  pressure  from  the  center  than  is  required  in 
large  work.  A  small  center,  then,  for  small  work 
is  as  serviceable,  comparatively,  as  a  large  center 
is  for  large  work. 

The  center  illustrated  in  the  middle  of  Fig.  4  has 
three  parts  as  does  the  stock  center,  but  two  of 
them,  A  and  B,  are  movable,  or  supposedly  so; 
whereas,  in  the  first  center  described,  only  one  part, 

A,  is  supposed  to  revolve.    A  is  a  piece  of  wood ;  B 
is  made  of  wrought  iron  or  steel;  C  is  preferably 
made  of  the  same  material  as  B.    It  has  been  stated 
that  both  A  and  B  are  supposed  to  revolve.     Such 
revolution  is  not  necessary,  however.    If  A  revolves 
upon  B,   the   necessary  requirements  are  fulfilled ; 
or,  if  A  and  B  together  revolve,  the  same  results 
are  obtained ;  likewise  if  A  revolves  slightly  upon 

B,  and  B  revolves  slowly  in  C,  the  same  result  is  ob- 
tained.     Herein    lies    one    supposed    or    imaginary 
advantage   which    this   center   has   over   the    stock 
center,  viz,  that  if  one  part,  A,  sticks  upon  another, 
B, — similarly  if  B  sticks  in  C — there  still  remains  the 
possibility  of  a  perfect  bearing  at  a  second  point. 
While  this  is  undoubtedly  true,  there  is  always  the 
possibility  of  both  A  and   B  sticking,  and  as  this 
center  has  more  parts  than  the  others,  there  is  more 
danger  of  its  getting  out  of  order.    Furthermore,  as 
A  is  made  of  wood,  it  will  burn  as  it  revolves  upon 
B,  unless  the  movement  between  A  and  B  is  slight, 
or  A  is  well  lubricated  upon  B.    Of  course,  it  is  an 


20  METAL  SPINNING 

easy  matter  to  duplicate  A,  and  it  may  be  said  here 
that  it  is  well  to  have  a  number  of  this  part  of  the 
center  in  stock.  A  broom  handle,  sawed  into  one- 
inch  lengths  with  the  proper  hole  drilled  at  the 
center  of  each  sawed-off  part,  will  provide  pieces 
for  a  considerable  length  of  time. 

There  is  an  idea  among  some  spinners  that  the 
part  coming  in  contact  with  the  metal  to  be  spun 
should  be  made  of  wood  so  that  a  better  "stick"  may 
be  secured  than  is  possible  with  a  metal  end. 
Whether  this  is  a  fact  or  not,  however,  must  be  de- 
cided by  each  workman.  It  is  sometimes  found 
advantageous  to  put  a  little  resin  on  the  end  of  the 
center  in  order  to  increase  the  friction  between  it 
and  the  metal  to  be  spun.  Again,  when  the  part  A 
is  made  of  wood,  it  is  possible  to  drive  into  the  end 
next  to  the  work  a  few  small  brads.  These  may  be 
left  extending  from  the  center-end  just  enough  to 
catch  on  the  disk  as  it  revolves  in  the  spinning 
process. 

Any  one  of  the  three  centers  described  work  well, 
but,  as  has  been  intimated,  not  at  all  times  per- 
fectly. I  believe  there  is  an  opportunity  for  some- 
one to  devise  a  more  perfect  spinning  center.  I  have 
wondered  if  some  ball  bearing  center  might  not 
solve  the  present  difficulties.  Such  a  center  is  illus- 
trated in  Fig.  4.  It  has  been  used  with  success  in 
school  work  according  to  the  statement  of  the  in- 
dividual who  devised  it. 


CHAPTER  II 
TOOLS 

The  tools  used  by  metal  spinners  are  difficult  to 
name.  Very  few  spinning  operations  require  the 
use  of  any  one  particular  tool.  This  fact  contributes 
to  the  present  condition  regarding  metal  spinning 
tools  in  general,  viz : — They  are  usually  not  to  be 
found  in  stock  and,  when  found,  the  forms  used  for 
the  different  processes  vary  considerably  in  differ- 
ent sections  of  the  country.  There  are  a  few  stand- 
ard forms,  however,  and  while  it  is  true  that  old 
spinners  usually  make  their  own  tools,  they  con- 
form to  regular  practice  in  making  these  few  stand- 
ard forms. 

The  tools  commonly  spoken  of  by  the  machinist 
as  the  hand-tool  diamond  point  and  the  cut-off  tool 
are  the  only  edge  tools  used  in  metal  spinning ; 
consequently,  there  is  little  danger  of  the  operator 
being  cut  while  spinning  metal.  To  aid  further  in 
eliminating  the  factor  of  danger  in  the  use  of  tools, 
nearly  all  spinning  tools,  except  the  above-men- 
tioned two,  may  be  used  with  the  end  of  the  tool 
placed  under  the  work.  In  most  lathe  processes  the 
tools  are  pushed  into  a  revolving  piece  or  placed  on 
top  of  it  as  is  the  case  in  some  kinds  of  wood  turn- 
ing. This  feature  of  comparative  safety  is  one 
which  recommends  itself  to  many  who  contemplate 
starting  metal  spinning  in  schools. 

Because  all  spinning  tools  are  used  by  pressing 
their  ends  against  the  work,  considerable  friction 


22  METAL  SPINNING 

results,  and  to  minimize  this  as  much  as  possible, 
the  tools  in  a  spinner's  kit,  except  those  mentioned 
for  cutting  and  trimming  (the  diamond  point  and 
cutting-off  tools),  should  be  ground  perfectly 
smooth  and  then  well  polished  with  emery. 

I  have  said  it  is  difficult  to  find  spinners'  tools 
kept  in  stock.  Perhaps  this  is  the  reason  why  their 
names  are  not  well  known.  In  talking  with  an  old 
spinner  concerning  the  names  of  the  tools  in  his  set, 
he  said,  "Why  sir,  I  have  been  a  spinner  for  thirty 
years  in  Sweden  and  in  the  United  States  and  it 
seems  as  though  I  had  always  known  how  to  use 
every  tool  on  this  shelf,  but  I  cannot  give  you  the 
name  of  one  of  them.  As  a  boy  I  was  carefully 
taught  how,  why  and  where  to  use  each  one  but  I 
always  heard  them  called  'this  tool'  or  'that  tool.' 
I  don't  believe  they  have  any  names."  I  suggested 
that  no  one  ought  to  be  better  prepared  to  name 
spinners'  tools  than  he  after  his  life's  experience  and 
so,  with  some  persuasion,  he  suggested  the  names 
which  I  shall  use  in  connection  with  the  tools  de- 
scribed and  illustrated  in  the  next  few  pages.  Some 
were  named  because  of  their  shape,  and  for  others 
names  were  suggested  by  the  kind  of  work  which 
they  performed. 

In  the  average  set  of  tools  in  an  expert  spinner's 
set  will  be  found  from  one  to  two  dozen  forms. 
Perhaps  not  more  than  six  or  eight  tools  are  in  or- 
dinary use.  As  it  is  with  most  specialists,  the 
individual  metal  spinner  will  collect  a  number  of 
forms  which  he  will  use  only  once  in  a  great  while. 
I  shall  make  reference  to  only  six  of  the  more  im- 
portant tools  here,  and  I  venture  to  say  from  some 


METAL  SPINNING  23 

experience  that  any  spinning  except  that  which 
may  be  designated  as  "special"  can  be  done  with  a 
part  or  all  of  these. 

The  round-nose,  Fig.  5,  is  made  of  %-in.  round, 
hexagonal  or  octagonal  steel.  Round  stock,  for  the 
work  which  this  tool  does,  is  probably  the  best.  It 
is  forged  into  the  desired  shape  and  at  least  3  in.  of 
the  end  carefully  ground ;  probably  one-half  or  more 
of  this  distance  ought  to  be  polished.  The  kind  of 
work  to  be  done,  and  the  peculiar  tastes  of  the 
workman  can  alone  determine  the  exact  shape  most 
suitable  for  this  or  other  tools.  For  this  reason  two 
or  three  round-nose  tools,  varying  in  form  from  the 
long  to  the  short  pointed,  may  be  used  to  advan- 
tage. The  extreme  end  must  not  be  a  sharp  point 
in  any  case  for  fear  of  its  catching  the  revolving 
metal  and  tearing  it.  It  is  advisable,  however,  in 
order  to  press  the  tool  into  small  grooves,  to  have 
the  end  as  pointed  as  possible  and  yet  have  it 
slightly  rounded. 

The  round-nose  is  used  to  a  greater  or  less  degree 
according  to  the  regularity  of  form  in  the  object 
being  spun,  but,  in  general,  it  is  used  to  the  exclu- 
sion of  all  others  in  starting  to  spin  a  piece,  and  by 
many  workmen  it  is  used  more  than  any  other  one 
tool.  It  is  especially  useful  in  compressing  metal 
into  cavities  and  in  pressing  out  any  irregularities 
or  wrinkles  before  removing  work  from  the  lathe. 

The  tool  which  is  probably  as  difficult  of  con- 
struction as  any  is  shown  in  Fig.  6  and,  for  lack  of 
a  better  name,  will  be  called  the  raising-up  tool. 
As  this  tool  is  used  in  operations  which  require 
considerable  force  applied  by  the  workman,  and, 


24 


METAL  SPINNING 


V 


c 


METAL  SPINNING  25 

also,  because  in  forging  the  tool  a  neck  is  formed 
smaller  than  the  regular  stock,  it  is  well  to  use  steel 
a  trifle  larger  than  that  used  for  the  round-nose. 
Where  ^-in.  stock  is  used  for  the  tool  just  de- 
scribed, %-in.  or  even  %-in.  material  can  profitably 
be  used  in  the  construction  of  the  one  now  under 
discussion.  Hexagonal  or  octagonal  steel  is  gener- 
ally considered  more  desirable  for  the  raising-up 
tool  than  round  stock.  The  forging  of  this  tool 
must  be  done  with  a  great  deal  of  care.  The  first 
process  is  to  upset  the  end  of  the  tool.  The  second 
process  is  to  draw  down  the  neck,  leaving  a  knob 
of  metal  on  the  end  which  is  sufficient  in  size  to 
form  the  finished  end.  There  is  one  danger  against 
which  the  forger  must  constantly  guard  in  upset- 
ting and  hammering  the  tool  into  shape.  I  refer  to 
the  leafing  or  lapping  of  metal  which,  unless  a  weld- 
ing heat  is  reached,  will  leave  seams  in  the  finished 
tool  that  will  make  it  almost  useless.  Again,  in 
tempering,  great  care  must  be  taken  not  to  produce 
a  crack  in  the  neck  just  back  of  the  head.  The  use 
to  which  the  raising-up  tool  is  principally  put — 
that  of  forming  concave  bottoms  on  dish  forms  or 
operations  which  require  surfaces  to  be  spun  con- 
cave instead  of  convex  toward  the  headstock — 
makes  it  necessary  that  the  head  of  this  tool  should 
have  a  lobe  left  at  the  point  lettered  A,  Fig.  6,  in 
order  that  the  tool  can  hook  under  the  metal  and 
draw  it  up  into  an  undercut  groove. 

I  have  endeavored  to  make  the  drawings  of  these 
tools  as  nearly  correct  as  possible  according  to  the 
suggestions  which  I  have  received  from  spinners 
and  from  my  own  experience,  and  in  the  case  of  this 


26 


METAL  SPINNING 


METAL  SPINNING  .27 

particular  tool  the  form  as  illustrated  has  been 
made  with  special  care.  It  should  be  noticed  that 
the  surfaces  CD  and  EF  are  slightly  convex  out- 
ward. 

The  planisher  is  the  name  given  to  the  tool  con- 
sidered third  in  importance.  Hexagonal  %-in.  steel 
is  used  to  make  it  and  is  hammered  into  the  form 
shown  in  Fig.  7.  All  that  portion  of  the  steel  which 
has  been  changed  in  shape  by  forging  the  tool 
should  be  ground  and  polished.  Especially,  should 
care  be  taken  to  have  the  two  flat  tapering  surfaces 
true  and  perfectly  smooth.  It  is  quite  important, 
also,  that  the  end  should  be  straight  with  reference 
to  the  width  of  tool  and  neatly  rounded  with  refer- 
ence to  the  thickness.  The  principal  use  to  which  this 
tool  is  put  is  that  of  a  burnisher.  It  is  used,  there- 
fore, almost  entirely  as  a  finishing  tool.  The  flat 
surfaces  are  placed  against  cylindrical  or  conical 
surfaces  and  the  end  is  used  in  perfecting  small 
grooves  by  pushing  it  into  the  concavity  as  one 
would  push  a  cutting-off  tool  into  a  piece  of  spindle 
wood  turning. 

So  far  we  have  spoken  of  tools  which  seem  to 
have  been  designed  to  make  concave  surfaces,  prin- 
cipally, such  as  large  or  small  grooves  or  cup- 
shaped  formations.  The  tongue  tool  shown  in  Fig. 
8  has  its  principal  use  in  forming  convex  surfaces, 
or?  as  the  spinners  sometimes  say,  in  "turning  over" 
the  metal.  It  is  usually  made  from  stock  as  small 
or  smaller  than  that  used  in  the  construction  of  the 
other  tools  described.  The  planisher  is  used  in  its 
stead  when  large  convex  surfaces  are  spun.  It  is 
not  necessary  that  the  tongue  should  be  forged.  If 


28 


METAL  SPINNING 


METAL  SPINNING  29 

care  is  taken,  the  flat  surface  can  be  ground  without 
burning  the  steel.  This  flat  surface  is  the  part  of  the 
tool  which  is  used  principally ;  the  one  operation  of 
grinding  together  with  polishing  puts  it  in  condi- 
tion. It  is  well  to  have  the  cylindrical  part  of  the 
tool,  opposite  the  flat  surface,  ground  and  polished. 
This  surface  can  sometimes  be  used. 

It  is  believed  that  the  tools  of  which  mention  has 
already  been  made  might  conclude  the  list  of  those 
making  up  the  necessary  tools  in  a  spinner's  kit.  if 
it  were  not  for  some  extraordinary  or  unusual 
shapes  in  spun  work.  For  the  purpose  of  spinning 
these  peculiar  forms  special  tools  may  be  made  at 
any  time. 

There  are  two  other  tools,  the  groover  and  the 
knob-raising  tool — illustrated  in  Figs.  8  and  9  re- 
spectively— which  may  be  used  in  places  as  substi- 
tutes for  those  already  described,  with  perhaps 
some  additional  ease. 

The  groover,  as  the  name  implies,  is  used  in  mak- 
ing grooves.  The  operator  finds  the  use  for  this 
tool  almost  entirely  in  spindle  forms  and,  then,  only 
for  small  grooves.  It  will  be  noticed  from  the  cross- 
sectional  view  shown  that  small  grooves  of  varying 
sizes  may  be  made  by  simply  using  the  tool  in  con- 
tact with  the  metal  at  different  points  on  the  curve 
of  the  tool.  It  is  placed  on  top  of  the  lathe-rest  with 
the  end  hanging  down  and  on  the  lathe  side  of  the 
rest.  The  operator  presses  down  on  the  handle, 
thus  making  a  lever  of  the  tool  with  the  rest  as  the 
fulcrum. 

As  will  be  discerned  later,  the  knob-raiser  may  be 
used  in  raising  up  or  hooking  under  the  metal  in 


30  METAL  SPINNING 

spinning  a  dish  concave  toward  the  headstock;  or 
it  may  be  used  by  pressing  it  endwise  toward  the 
line  of  centers  on  the  lathe,  to  form  a  concavity  on 
a  spindle  form.  It  should  be  a  comparatively  easy 
matter  to  forge  the  knob-raiser,  inasmuch  as  the 
end  is  simply  upset  in  the  fire  and  afterwards 
ground  into  the  desired  shape  and  polished. 

Figure  10  gives  the  shape  and  the  dimensions  of 
the  accepted  handle  for  spinning  tools.  In  this 
figure,  also,  is  represented  the  method  used  in  fas- 
tening the  tool  into  the  handle.  Probably  the  best 
wood  out  of  which  handles  may  be  turned  is 
straight-grained,  hard  maple. 

It  is  necessary  that  all  tools,  except  those  used 
for  cutting  and  trimming  purposes,  should  be  long 
enough  to  permit  the  end  of  the  handle  to  rest  under 
the  arm  and  thus  aid  the  workman  in  getting  a 
strong  leverage  by  throwing  the  weight  of  his  body 
downward.  The  handles  are  usually  made  from  12 
to  15  in.  in  length  and  the  tool  long  enough  to  admit 
of  its  being  driven  into  the  handle  from  4  to  5  in. 
Pieces  of  gas  or  water  pipe  make  very  good  ferrules. 
The  tool  and  handle  when  fastened  together  should 
be  from  2  ft.  to  30  in.  in  length.  Inasmuch  as  the 
tools  are  highly  tempered,  the  wearing  due  to  the 
spinning  process  does  not  change  their  shape  rap- 
idly. Consequently,  reforging  is  not  necessary 
except  after  the  tool  has  been  in  service  for  a  con- 
siderable length  of  time. 


CHAPTER  III 

THE  PREPARATION  OF  METAL  FOR 
SPINNING 

The  metals  commonly  used  in  spinning  are  cop- 
per, white  metal,  brass,  zinc  and  aluminum.  Metals 
must  be  used  which,  by  some  process  such  as  an- 
nealing, can  be  made  perfectly  pliable.  It  must  be 
evident  that  only  when  metal  is  perfectly  pliable 
can  it  be  spun  over  irregular  shapes.  The  constant 
friction  between  the  tool  and  the  metal  tends  to 
harden  the  metal,  and  hence  it  must  be  softened 
and  made  pliable,  many  times  it  may  be,  during  a 
spinning  process. 

The  thickness  of  metal  most  suitable  for  ordinary 
work  varies  from  Brown  and  Sharpe  gage  No.  22 
to  No.  26,  inclusive.  Metal  gaging  22  is  used  for 
the  largest  work  only  and  then  principally  when 
the  metal  is  copper.  Gage  24  in  brass  and  zinc  be- 
comes pliable  with  proper  treatment  and  can  be 
successfully  used  for  forms  varying  in  diameter  and 
height  from  3  in.  up  to  5  or  6  in.  Metal  of  B.  and 
S.  gage  No.  26  is  more  easily  spun  than  thicker 
material,  due  to  the  fact  that  it  assumes  easily  and 
quickly  the  desired  form.  Because  of  this  fact, 
however,  articles  spun  from  it  are  sooner  ruined 
than  those  spun  from  thicker  metal.  Gage  26  will 
not  stand  the  continual  pressure  of  the  spinning 
tool  very  long.  Metal  of  No.  26  gage  is  naturally 
adapted  to  the  smallest  work,  but  to  be  successfully 
spun  should  be  used  by  workmen  of  some  experi- 
ence. 


32  METAL  SPINNING 

Thus  far  we  have  spoken  of  metals  in  a  general 
way,  and  of  no  one  metal  in  particular.  We  will  dis- 
cuss briefly  the  preparation  and  best  uses  of  the  four 
metals  mentioned  above. 

Copper 

Copper,  varying  in  thickness  between  the  gages 
referred  to  above,  is  perhaps  most  suitable  for  all 
general  spinning,  especially  for  school  work  and  for 
amateurs.  It  is  tough  and  when  heated  is  very 
pliable.  It  is  not  so  easily  shattered  by  overheat- 
ing, numerous  heatings  or  long  continuous  working 
as  are  the  other  metals  mentioned.  It  should  be 
understood  that  all  operations,  in  preparing  the 
metal  for  spinning  and  those  used  after  spinning  is 
begun,  should  be  as  brief  as  possible  and  never 
duplicated  unless  necessary.  As  a  matter  of  fact 
the  annealing  process  will  be  repeated  many  times 
of  necessity,  especially  by  beginners.  In  learning 
to  spin,  one  will  keep  the  tool  in  one  place  on  the 
metal  until  it  becomes  hard  and  tempered  in  a 
sense.  As  a  young  spinner  will  probably  find  diffi- 
culty in  successfully  producing  a  desired  form  in 
one  operation  it  will  be  necessary  for  him  to  anneal 
or  soften  the  copper  before  he  completes  spinning. 

One  must  first  calculate,  with  some  degree  of  pre- 
cision, the  size  of  circular  disc  necessary  to  form  the 
spun  article.  If  spinning  is  properly  done,  the 
metal  will  be  thinned  very  little,  if  any,  in  working 
it;  consequently  the  computation  of  the  disc  size 
will  involve  in  most  cases  some  mensuration,  but, 
principally,  a  good  supply  of  common  sense  and 
judgment  is  needed.  The  workman  will  be  greatly 
aided  in  his  computation  if  he  will  make  a  cross- 


METAL  SPINNING  33 

sectioned  drawing  (through  the  axis  of  revolution) 
of  the  object  he  is  spinning,  and,  with  a  pair  of  divid- 
ers, set  to  a  small  span,  step  off  the  length  of  the 
outline  desired.  Thus  if  in  B,  Fig.  11,  (Cup  and 
Chucks)  one  should  start  at  O  and  step  carefully 
by  1  and  2  to  3  he  would  have  the  radius  of  the  disc 
out  of  which  the  cup  could  be  spun.  It  will  be  de- 
sirable to  make  the  radius  of  the  disc  slightly 
greater  than  the  distance  thus  determined,  if  the 
metal  is  to  be  compressed  any.  If,  on  the  other 
hand,  the  metal  is  thinned  due  to  unnecessarily 
working  the  tool  over  the  metal,  the  radius  need  not 
be  quite  as  large  as  the  outline  distance  spoken  of. 

The  disc  after  being  cut  from  a  large  sheet — in 
which  form  the  metal  is  best  purchased — is  heated 
in  an  annealing  furnace  or  over  a  Bunsen  burner 
until  it  changes  to  an  iridescent  color  and  a  film  of 
copper  oxide  burns  off.  If  an  annealing  furnace  is 
used,  the  temperature  may  be  controlled ;  but  in 
case  a  Bunsen  burner  or  blow-lamp  is  used — one  of 
which  methods  would  be  followed  probably  for 
small  work — the  coloring  of  the  metal,  when  the 
proper  temperature  is  reached,  must  be  the  means 
of  determining  when  the  copper  has  been  heated 
sufficiently.  If  it  is  heated  beyond  the  proper  point 
the  strength  of  the  metal  is  weakened  and  it  may  be 
even  exhausted  entirely.  Nevertheless,  in  rough 
work,  copper  is  heated  until  it  is  "red"  hot  and  im- 
mediately plunged  in  water.  This  constitutes  the 
annealing  process.  Some  spinners,  especially 
where  considerable  care  is  taken  to  preserve  the 
strength  of  the  metal,  cover  copper  with  oil  when 
annealing  it.  This  is  by  no  means  an  undesirable 


34 


METAL  SPINNING 


METAL  SPINNING  35 

plan.  The  film  of  oil  will  evaporate  and  burn  off  as 
heat  is  applied ;  when  the  oil  has  completely  disap- 
peared the  metal  should  be  annealed.  This,  as  well 
as  the  first  method  described,  will  not  necessarily 
give  accurate  results.  Both  methods  are  simple, 
practical  means  which,  together  with  a  little  experi- 
ence, will  aid  in  reaching  uniform  results. 

If  very  precise  work  is  necessary,  as,  for  example, 
in  spinning  some  article  which  must  be  kept  under 
intense  pressure,  the  best  temperature  for  anneal- 
ing must  be  carefully  ascertained  by  experiment. 
In  this  case  the  annealing  or  some  similar  furnace 
should  be  used  where  accurate  temperatures  can  be 
recorded. 

To  make  this  description  perfectly  clear  it  may 
be  said  that  the.  following  steps  should  be  taken  in 
spinning  a  piece  of  copper. 

First :  Cut  from  a  plate  of  soft  copper  a  circular 
disc  of  a  calculated  size  to  spin  from  it  a  particular 
object. 

Second :  If  the  copper  is  not  quite  soft  and 
pliable  heat  it  to  a  red  heat  and  immediately  plunge 
it  into  cold  water. 

Third :  Place  the  disc  in  the  lathe  ready  to  spin. 
Apply  the  tool  to  it  until  the  copper  begins  to 
harden  perceptibly. 

Fourth :  Remove  the  copper  from  the  lathe  and 
anneal  as  previously  described. 

Fifth:  Repeat  the  above  instructions  in  the 
order  given  as  few  times  as  possible,  but  until  the 
spinning  process  is  completed. 

White  Metal 
White  metal   is  very  easily  spun   and  does  not 


36  METAL  SPINNING 

need  to  be  annealed.  In  the  trades  it  is  used  as  the 
base  for  most  silver-plated  ware ;  and  consequently 
for  forms  which  cannot  be  pressed  out,  the  spinning 
process  is  a  necessary  one.  If  the  lightness  of  the 
plated  piece  has  not  a  large  consideration  in  its 
production,  it  is  advisable  to  use  quite  heavy  white 
metal.  There  will  be  an  explanation  made  in  a 
future  chapter  concerning  the  drawing-out  of  metal 
in  spinning.  As  the  spinning  process  continues,  the 
metal  is  liable  to  be  worked  thin  by  being  drawn 
out.  This  is  especially  true  in  the  case  of  white 
metal  and  thus  the  suggestion  with  reference  to  the 
use  of  heavy  metal  is  opportune. 

Brass 

Brass  is  prepared  for  spinning  in  the  manner  de- 
scribing the  annealing  of  copper.  The  change  of 
color  in  brass  is  not  so  perceptible,  when  sufficient 
heat  has  been  applied,  as  in  copper,  and  conse- 
quently the  method  of  covering  the  metal  with  oil 
before  heating  will  probably  be  the  safest  in  anneal- 
ing brass.  For  ordinary  spinning  it  is  quite  imma- 
terial whether  or  not  one  applies  the  same  amount 
of  heat  for  each  annealing,  so  long  as  the  metal  is 
not  overheated.  Brass  hardens  more  rapidly 
through  the  use  of  the  spinning  tool  than  copper 
does.  When  we  remember,  then,  that  there  is 
greater  danger  of  spoiling  the  metal  by  annealing 
it  many  times  than  by  slightly  overheating  it  once, 
we  will  understand  why  brass  is  more  difficult  to 
spin  than  copper.  Wherever  possible,  one  should 
use  as  thin  brass  as  will  be  consistent  with  the 
strength  required. 


METAL  SPINNING  37 

Zinc 

We  have  said  that  it  was  perhaps  advisable  to  im- 
merse copper  and  brass  in  oil  before  annealing. 
This  is  still  more  important  with  zinc.  Whether  it 
is  necessary  or  not  to  oil  or  grease  zinc  while  heat- 
ing it  may  be  a  question,  but  it  is  certainly  advisable 
in  the  minds  of  old  spinners.  The  theory  seems  to 
be  that  the  oil  tends  to  soften  the  metal  when  heat  is 
applied.  Zinc  has  a  decidedly  crystalline  formation 
and  the  friction  caused  by  the  spinning  tool  rubbing 
against  it  tends  to  make  it  more,  rather  than  less, 
crystalline.  This  molecular  condition  weakens  the 
metal  by  decreasing  its  tensile  strength  and  it  be- 
comes decidedly  difficult  to  spin;  especially  is  this 
true  in  thick  pieces  which  have  to  be  turned  over 
abrupt  corners.  The  melting  point  for  zinc  is  about 
780°  Fahrenheit,  which  is  considerably  lower  than 
the  melting  point  for  copper  or  good  brass.  This 
necessitates  much  more  care  in  annealing  zinc  than 
is  necessary  with  any  other  metal  which  is  capable 
of  being  spun.  It  is  decidedly  advisable  not  to 
reach  a  temperature  above  350°  or  400°  F.  Of 
course  this  point  in  temperature  cannot  be  deter- 
mined except  in  an  annealing  furnace.  It  should  be 
understood  that  after  zinc  is  heated  as  above  ex- 
plained it  is  plunged  into  cold  water  before  any 
attempt  is  made  to  spin  it. 

Aluminum 

Ordinarily,  aluminum  does  not  need  annealing. 
It  may  be  better  to  heat  it  slightly  when  the  metal 
is  thick,  but  this  is  a  matter  which  the  operator 
must  determine  for  himself  by  experiment.  Like 
white  metal,  aluminum  is  easily  worked,  but  it  is 


38  METAL  SPINNING 

also  easily  shattered;  and  consequently  the  ease 
with  which  it  can  be  spun  sometimes  results  in  a 
spoiled  piece  after  considerable  work  has  been  done 
on  it.  Aside  from  the  point  of  its  being  a  good  base 
for  plated  ware,  there  is  no  advantage  in  using 
aluminum.  It  is,  however,  light,  and  therefore  may 
be  desirable  to  use  for  large  spun  pieces. 


CHAPTER  IV 

HOW  TO  SPIN  A  SHALLOW  DISH 

The  very  simplest  spinning  operations  possible 
are  involved  in  the  spinning  of  a  shallow  dish  of 
small  diameter,  such  as  a  pin  tray.  Shallow  forms 
may  be  difficult  to  spin,  however,  if  they  are  irreg- 
ular and  complicated  in  cross-sectional  outline. 
The  one  thing  which  makes  them  good  examples 
for  amateurs  is  their  shallowness.  They  should  be 
simple  in  form,  also,  if  they  are  first  pieces  in  spin- 
ning. I  should  say  the  amount  of  depression  should 
not  exceed  1  in.  and  the  diameter  should  not  be 
greater  than  6  in.  in  the  spinner's  initial  dish. 

A  shallow  dish  may  be  in  either  of  two  general 
classes,  depending  upon  form,  viz : — one  in  which 
the  curve  of  depression  is  gradual  from  the  rim  to 
the  bottom ;  or  one  in  which  the  bottom  of  the  dish 
is  comparatively  flat  and  the  rim  is  formed  by 
abruptly  turning  the  metal  over  a  corner,  the  rim 
being  perpendicular  to  the  general  plane  of  the  bot- 
tom. In  the  first  class  we  find  the  saucer,  and  in 
the  second  such  a  form  as  the  cover  to  a  tin  box — 
a  baking-can,  for  example. 

It  will  be  evident  that  one  of  two  things  will  tend 
to  make  a  dish  difficult  to  spin ;  either  its  great 
depth  or  some  sharp  corner  which  forms  the  divid- 
ing line  between  two  surfaces.  Right  angle  corners, 
therefore,  are  difficult  to  spin ;  especially  so  when 
the  surface  turned  over,  as  in  the  rim  of  a  dish,  is 
very  high. 


40  METAL  SPINNING 


Attractive  in  Shape  and  Finish 


METAL  SPINNING  41 

Either  of  the  two  faceplates  sent  with  a  wood- 
turning  lathe  may  be  used  for  the  wooden  form- 
blocks  over  which  the  metal  is  spun.  It  is  best  to 
use  the  center-screw  faceplate  for  work  of  small 
diameter,  such  as  a  cup,  for  example;  and  the  sur- 
face-screw faceplate  for  work  of  large  diameter.  If 
this  suggestion  is  followed,  one  will  probably  use 
the  surface-screw  faceplate  to  spin  low  dish  forms. 
The  wooden  form-block  is  made  according  to  ac- 
cepted methods  of  wood-turning.  Two  things  must 
be  true  if  the  form  is  to  serve  satisfactorily  the  pur- 
pose for  which  it  was  turned :  It  must  be  perfectly 
smooth  and  it  must  be  hard.  Hard  maple,  well- 
scraped  and  sandpapered,  makes  a  very  good  form 
for  most  spun  work. 

In  some  cases,  as  will  be  illustrated  later,  it  is 
necessary  to  split  a  form  in  order  to  release  it  from 
the  spun  article.  Dogwood  is  considered  the  best 
for  this  purpose,  although  straight-grained  hard 
maple  will  answer  the  purpose  very  well.  When  a 
number  of  one  particular  form  are  to  be  spun,  it  is 
economy  of  time  and  labor  to  construct  a  cast-iron 
form-block.  It  is  best  not  to  loosen  a  form-block 
from  the  faceplate  after  it  is  once  put  in  place  until 
all  spinning  is  finished.  This  may  require  the  con- 
struction of  duplicate  faceplates  for  each  lathe  in 
case  a  lathe  is  used  for  some  purpose  besides  the 
one  in  question  before  a  spinning  job  is  completed. 
It  is  better  to  do  this,  however,  than  to  have  the 
work  running  out  of  true  due  to  removing  the  form- 
block  from  a  faceplate  to  allow  other  work  to  be 
put  on  it. 

When  the  metal  disc  has  been  cut  and  centered 


a&.    ^\^ 

%^^^^ 


Artistic  Designs 


METAL  SPINNING  43 

moderately  well  in  the  lathe  between  the  spinners' 
center  and  the  form  over  which  it  is  to  be  spun,  the 
workman  is  ready  to  begin  spinning.  (A  cut  show- 
ing the  work  in  this  stage  is  found  on  page  14.) 
It  will  be  remembered  from  the  discussion  on  spin- 
ners' centers  that  at  first  nothing  holds  the  disc  in 
a  central  position  except  the  pressure  of  the  center 
against  the  piece  to  be  spun. 

It  is  necessary  to  keep  metal  well  greased  when 
spinning  it.  Before  putting  it  in  the  lathe  it  is  well 
to  apply  whatever  lubricant  is  to  be  used,  and  dur- 
ing the  spinning  process  to  make  further  applica- 
tions whenever  the  disc  becomes  dry  or  at  any  time 
after  it  is  annealed.  Soft  soap  is  considered  as  sat- 
isfactory as  anything  to  use  on  copper.  On  brass 
and  zinc  spinners  rub  a  tallow  candle  and  this  may 
be  used,  too,  on  copper.  White  metal  and  alumi- 
num need  only  a  little  heavy  oil  from  time  to  time 
to  keep  the  tool  from  grinding  the  metal. 

The  illustration  on  page  14,  Fig.  3,  shows  the 
general  position  of  spinning  tool  and  workman 
when  the  spinning  process  begins.  In  the  right 
hand,  with  the  handle  under  the  right  arm  above 
the  elbow,  is  held  the  spinner's  tool  and  in  the  left, 
the  end  of  a  broom  handle  or  some  hard  piece  of 
wood  of  similar  shape.  Until  it  is  possible  to  press 
the  metal  firmly  against  the  form-block  fastened  on 
the  faceplate  the  end  of  the  piece  of  wood  held  in 
the  left  hand  is  kept  opposite  the  end  of  the  tool  as 
it  moves  from  the  center  of  revolution  outward  and 
downward.  The  piece  of  metal  as  it  is  revolving 
has  a  piece  of  wood  (tapered  to  allow  a  flat  surface 
to  come  in  contact  with  the  spinning  metal)  on  its 


44  METAL  SPINNING 

left,  and  the  spinning  tool  on  its  right.  The  revolu- 
tion of  the  lathe  draws  the  tool  down  so  that  it  is 
nearer  the  axis  and  a  little  lower  than  the  end  of 
the  wooden  support  held  in  the  left  hand.  The  body 
throws  the  handle  to  the  right,  which  causes  the 
end  of  the  tool  to  press  to  the  left  and  consequently 
move  the  metal  gradually  toward  and  finally 
against  the  form-block.  When  the  metal  has  at 
last  been  spun  tightly  against  the  form-block,  the 
diamond  point  is  used  to  trim  the  edge  and  the  spun 
piece  is  complete.  Usually  in  spinning  a  low  dish 
of  regular  shape  it  is  not  necessary  to  anneal  the 
metal  after  it  is  first  put  in  the  lathe.  It  should  be 
understood,  however,  that  annealing  is  necessary 
whenever  the  metal  becomes  hard.  If  it  is  not  an- 
nealed as  soon  as  it  becomes  hard  it  will  shatter. 

The  spinning  process  may  be  accomplished  also 
by  holding  the  tool  as  described,  except  to  have  the 
tool  end  above  the  center  of  the  lathe  instead  of  be- 
low it.  If  this  position  is  taken,  the  movement  of 
the  body  must  be  two-fold,  viz :  downward  and  to 
the  right,  which  will  result  in  the  tool  point  work- 
ing upward  instead  of  downward. 

Probably  in  spinning  a  simple  dish  form  no  diffi- 
culty will  be  experienced  in  keeping  the  metal  to  a 
uniform  thickness  and  the  same  thickness  approx- 
imately as  it  was  in  the  sheet.  If,  however,  it  is 
found  that  the  metal  is  thinning,  the  tool,  by  revers- 
ing the  movements  of  the  body,  must  be  made  to 
travel  toward  the  center  of  revolution.  This  will 
compress  instead  of  draw  out  the  metal.  It  must 
be  very  evident  that  an  inward  movement  of  the 
tool  point  will  tend  to  bulge  the  metal  at  the  point 


METAL  SPINNING  45 


Three  Attractive  Pieces 


46  METAL  SPINNING 

where  it  is  held  between  the  center  and  the  form- 
block.  It  is  to  avoid  this,  principally,  that  the  first 
movement  of  the  tool  is  taken  away  from  the  center 
or  axis.  Moreover,  the  metal  must  be  worked 
against  the  form,  at  first,  at  the  center  until  it  is 
firmly  in  contact  with  the  form-block.  This  is  very 
important.  If  spinning  is  successfully  done,  it  will 
be  largely  due  to  first  establishing  a  firm  contact  be- 
tween the  metal  and  its  form-block  at  the  center. 
Gradually  this  contact  surface  is  increased  as  the 
tool  continues  to  work  outward. 

It  has  been  assumed  that  the  dish  form  will  be 
spun  with  comparative  ease.  This  will  probably  be 
true  if  the  bulging,  just  referred  to,  and  buckling  do 
not  together  or  separately  hinder.  As  has  been  ex- 
plained, bulging  is  the  result  of  over-compression 
with  the  tool.  Buckling  is  one  phase  of  bulging. 
While  the  tool  is  working  toward  the  center,  bulg- 
ing may  take  place.  While  the  tool  is  working  out- 
ward and  when  it  is  pressing  against  metal  that  is 
not  in  contact  with  the  form-block  but  is  simply  be- 
ing supported  by  the  stick  in  the  left  hand,  buckling 
is  a  common  danger.  The  metal  begins  to  feel 
rough  under  the  tool  and  the  tool  will  seem  to  jump 
from  point  to  point.  Upon  investigation  it  will  be 
found  that  the  metal  is  folding  or  lapping  in  places. 
If  it  is  at  once  annealed,  the  difficulty  may  be  over- 
come, but  otherwise  it  will  continue  and  finally  the 
metal  will  shatter,  ruining  the  piece.  There  are  two 
reasons  for  this.  The  first  one :  the  stick  is  not  kept 
directly  opposite  the  tool  point,  and,  in  addition  to 
this,  is  probably  not  pressed  firmly  enough  against 
it.  It  may  be  true,  also,  that  pressure  is  being  ap- 


METAL  SPINNING  47 

plied  too  far  from  the  contact  surface,  yet  this  in 
large  work  must  be  true,  else  the  outer  portion  of 
the  metal  will  tend  to  curl  back  toward  the  tailstock 
and  the  metal  will  take  the  form  of  a  sombrero  hat. 
The  second  reason:  hard  metal.  With  amateurs 
this  is  often  the  principal  cause  of  buckling.  The 
only  remedy  is  to  anneal  the  metal  as  previously 
mentioned. 

It  must  be  remembered  that  lubrication  in  spin- 
ning is  quite  as  essential  as  the  use  of  oil  in  machine 


I 


Two  Popular  Forms 

bearings.  Soap  or  tallow  applied  often  and  in  small 
quantities  is  much  better,  as  experience  will  prove, 
to  both  metal  and  workman  than  large  quantities 
applied  less  frequently. 

The  speed  of  a  lathe  used  for  dish  spinning  de- 
pends somewhat  upon  the  diameter  of  the  disc 
when  spinning  is  commenced.  For  disc  diameters 
less  than  7  or  8  in.  a  speed  of  from  1500  to  1800 
r.p.m.  is  sufficient.  For  larger  diameters  lower 


48 


METAL  SPINNING 


speeds  are  required.  When  the  dish  has  finally 
been  formed  and  smoothing  and  polishing  are  the 
only  operations  left,  the  speed  may  profitably  be 
increased  to  2000  r.p.m.  or  even  more  than  this  for 
small  diameters.  Too  great  a  speed  will,  through 
centrifugal  force,  throw  the  metal  away  from  the 
form-block. 


CHAPTER  V 

HOW  TO  SPIN  A  DEEP  DISH 

Under  this  head  I  shall  treat  forms  which  ap- 
proach the  cylinder  and  require  the  use  of  two 
form-blocks  (for  beginners  at  least)  instead  of  one. 
The  illustration  on  page  42  shows  forms  of  this 
character — cups,  toothpick  and  match  holders,  etc. 
Spinning  metal  into  a  cylindrical  form  involves  a 
difficult  operation — that  of  turning  the  outer  por- 
tion of  the  circular  disc  which  is  being  spun, 
through  an  angle  approaching  90°  and  consequently 
compressing  very  materially  the  metal  at  the  outer 
portion  of  the  disc.  In  addition  to  this  there  is  the 
difficulty  of  turning  the  sharp  corner  between  the 
bottom  of  the  form  and  the  cylindrical  surface 
forming  the  sides.  An  experienced  hand  will  do 
both  of  these  things  with  apparent  ease  by  using 
the  tool  and  stick  as  described  in  Chapter  III. 
However,  as  the  metal  is  bent  or  turned  through  an 
angle  approaching  90°  the  operator  must  spin  in  the 
air,  as  it  is  called.  In  other  words,  nothing  sup- 
ports the  metal  from  the  time  it  leaves  the  circular 
disc  shape  until  it  reaches  the  finished  form  except 
the  tool  and  the  supporting  stick ;  the  metal  is  there- 
fore spinning  in  the  air.  If  one  is  proficient  in  the  art 
of  spinning  in  the  air,  only  one  form-block  will  be 
needed  for  deep  forms  as  was  the  case  with  shallow 
forms.  Few  men,  however,  are  capable  of  spinning 
large  pieces  in  the  air  when  the  metal  at  the  outer 
portion  of  the  disc  must  be  compressed  consider- 
ably. Intermediate  form-blocks  are  therefore  used. 


50  METAL  SPINNING 

To  explain  better  deep  dish  spinning  I  shall  refer 
to  a  specific  problem  which  I  have  shown  by  line 
drawings  on  page  34,  Fig.  11.  A  and  B  are  vertical 
cross-sections  through  two  form-blocks  which  in 
this  case  may  be  fastened  on  center  screw  face- 
plates, each  form-block  being  turned  and  kept  on  a 
single  faceplate  until  all  spinning  is  done.  A  is  the 
intermediate  form-block  and  B  the  finished  form- 
block  for  the  cup  illustrated  at  C,  Fig.  11.  The 
dotted  line  in  A  is  a  duplicate  of  the  form  B,  so  that 
one  can  easily  estimate  the  relative  amount  of  spin- 
ning which  must  be  done  on  each  block.  It  is  sup- 
posed that  the  metal  being  spun  will  be  annealed 
after  it  is  taken  from  form-block  A  and  before  it  is 
put  on  form-block  B. 

In  showing  only  one  intermediate  form-block  the 
writer  is  taking  it  for  granted  that  the  instructions 
given  in  Chapter  IV  will  enable  one  to  spin  the 
metal  on  each  of  the  two  form-blocks  without  diffi- 
culty. If  this  is  not  true  as  many  intermediate 
form-blocks  as  desired  may  be  prepared  consistent 
with  the  number  of  annealings  which  the  metal  will 
stand.  It  is  always  necessary  to  do  some  spinning 
in  the  air,  otherwise  the  supporting  stick  which  is 
held  in  the  left  hand  would  not  be  needed.  This 
supporting  stick,  however,  is  in  reality,  only  a 
makeshift  form-block,  and  when  the  intermediate 
form-blocks  are  many,  the  process  of  supporting 
the  metal  by  the  use  of  the  supporting  stick  is  not 
called  spinning  in  the  air. 

It  will  be  noticed  that  the  dotted  outline  and  the 
solid  outline  in  A  coincide  at  the  right,  not  only  on 
the  line  which  pictures  the  end  of  the  chuck,  but 
also  for  %  in.  or  %  in.  on  the  cylindrical  surface. 


METAL  SPINNING  51 

The  object  of  the  preliminary  form-block  and  all 
intermediate  form-blocks  hereafter  described  is 
two-fold :  first,  to  provide  easy  steps  in  the  process 
of  spinning;  and.  second,  to  give  a  contact  surface 
when  spinning  is  begun  on  succeeding  form-blocks. 
The  imagination,  I  believe,  will  easily  lead  one  to 
appreciate  the  significance  of  the  first  of  these  ob- 
jects, but  the  second  will  be  fully  appreciated  only 
when  one  has  endeavored  to  spin  some  form  similar 
to  the  one  illustrated  where  a  contact  surface  is  not 
maintained  throughout  the  spinning  process.  When 
the  metal  is  taken  from  form  A  and  put  on  form  B, 
a  portion  of  the  cup  is  in  its  final  shape  and  is  firmly 
seated  on  the  form-block  at  the  end,  making  the 
work  secure. 

The  method  of  bringing  the  metal  down  to  the 
block  B  after  the  block  A  has  been  produced  is 
somewhat  different  than  has  heretofore  been  de- 
scribed. In  obtaining  form  A  the  tool  has  been 
moved  outward,  with  possibly  a  few  exceptional 
strokes  of  the  tool,  toward  the  center.  This  has 
prevented  bulging  and  has  gradually  drawn  the 
metal  into  the  desired  shape  without  necessarily 
thinning  it.  If  this  same  manipulation  of  the  tool 
is  continued  when  the  intermediate  block  B  is  used 
the  metal  will  be  thinned  until  it  will  be  liable  to 
crack  before  the  form-block  is  reached  by  the  metal. 
Furthermore,  it  will  buckle  very  probably,  not  be- 
cause of  its  hardening  or  its  being  worked  too  far 
from  the  contact  surface,  but  because  it  is  thin  and 
consequently  weak.  For  these  reasons  the  tool  is 
moved  toward  the  axis  when  using  form-block  B. 
This  compresses  the  metal,  as  previously  described, 
decreasing  its  circular  measurements  and  at  the 


52  METAL  SPINNING 

same  time  thickening  it.  It  will  not  bulge  during 
this  process  because  the  base  of  the  cup  is  firm 
against  the  chuck.  It  must  not  be  supposed  that 
the  inward  movement  must  be  used  to  the  ex- 
clusion of  the  outward  one.  I  mean  to  infer  that 
the  former  should  predominate.  By  careful  work 
and  gradual  pressure  the  metal  will  finally  touch 
the  form-block  at  all  points. 

Mention  has  not  been  made  thus  far  of  the  tools 
to  be  used,  as  it  is  believed  enough  was  said  in 
Chapter  IV  to  enable  the  beginner  to  use  his  judg- 
ment in  the  selection  of  tools.  My  opinion  is  that 
the  round-nose  and  lifting  tool,  if  they  are  properly 
formed,  can  successfully  do  all  dish  and  cup  spin- 
ning of  an  ordinary  character.  For  the  purpose  of 
smoothing,  however,  some  tool  with  a  flat  surface, 
such  as  the  tongue  or  planisher,  will  undoubtedly 
be  used  with  more  facility  and  possibly  with  better 
results.  I  would  suggest  the  use  of  copper  or 
aluminum  for  all  work  thus  far  described,  if  strength 
of  material  is  an  object  and  if  the  operator  is  an 
amateur  of  spinning  work.  However,  white  metal 
is  more  easily  worked  than  copper  and  is  the  cus- 
tomary metal  for  the  base  in  plated  ware.  Brass 
is  rather  too  tough  and  hard,  and  zinc  is  too  brittle 
for  one  to  use  in  the  experimental  stage  of  spinning. 

If  considerable  difficulty  is  experienced  in  secur- 
ing the  desired  results,  I  offer  the  following  as  sug- 
gestive helps.  First : — Endeavor  to  spin  a  saucer 
of  small  diameter  and  of  simple  outline,  or  a  cup 
whose  sides  make  an  angle  of  about  75°  with  the 
base,  before  attempting  something  more  difficult. 


METAL  SPINNING 


53 


Second : — In  cup  spinning  use  three  or  even  four 
form-blocks,  if  perseverance  will  not  accomplish  the 
desired  result  with  two. 

The  speed  of  the  lathe  for  work  coming  in  the 
class  here  considered  can  be  a  trifle  higher  than 
that  given  as  average  in  a  previous  chapter. 


54 


METAL  SPINNING 


CHAPTER  VI 


HOW  TO  SPIN  A  VASE 

In  this  chapter  we  will  consider  all  forms  which 
may  be  called  vases.  In  some  cases  the  word  vase 
form  implies  a  neck  or  a  top  smaller  in  diameter 
than  the  bottom.  It  is  this  peculiarity  which  seems 
to  make  it  necessary  that  the  spinning  of  vases 
should  be  dealt  with  separately. 

The  manipulation  of  the  tools  in  this  group  or 
class  of  forms  will  be  spoken  of  briefly  as  very  few 
new  operations  in  tool  work  are  introduced.  Usual- 
ly a  greater  number  of  tools  are  required  to  com- 
plete a  vase  form  than  are  used  for  simpler  objects; 
these  will  be  mentioned  later. 

The  principal  variation  Irom  the  general  method 
of  work  comes  in  making  the  form-blocks.  Usually 
three  form-blocks  will  be  needed  for  a  vase-form 
which  has  a  neck  smaller  than  its  base,  unless  one 
is  an  adept  at  spinning  in  the  air.  As  this  book 
is  supposed  to  be  used  by  amateur  workmen,  as 
well  as  others,  I  shall  consider  that  preliminary  and 
intermediate  form-blocks  will  be  used  in  beginning 
work  at  least.  We  will  consider  a  specific  problem 
again  in  order  to  illustrate  and  describe  to  the  best 
advantage  detailed  methods  of  spinning.  Figure  12 
shows  vertical  cross-sectional  drawings  of  a  pre- 
liminary and  intermediate  chuck,  and  the  end  view 
and  elevation  of  the  final  form-block  used  in  spin- 
ning a  vase-form  represented  at  C  in  this  same  cut. 
In  Fig.  13  also  will  be  seen  a  vertical  cross-section 


56 


METAL  SPINNING 


METAL  SPINNING  57 

view  of  a  form-block  showing  the  construction  of 
a  block  or  chuck  for  a  vase  with  a  small  neck. 

Here  (Fig.  12),  as  in  Chapter  V,  A  and  B  are 
simply  used  as  easy  steps  in  obtaining  the  form 
shown  at  C.  It  is  only  necessary,  I  believe,  to  call 
attention  to  the  fact  that  the  diameters  shown  at  1 
and  2,  in  A,  B  and  C,  and  3,  in  B  and  C,  are  the  same. 
The  object  of  this  is  to  produce  contact  surfaces 
for  each  succeeding  form-block. 

One  is  not  advised  to  undertake  the  spinning  of 
a  vase-form  before  simpler  forms  have  been  tried. 
This  is  because  the  work  as  a  whole  is  more  difficult 
than  it  is  in  simpler  pieces.  There  is  a  particular 
difficulty,  too,  which  should  be  mentioned.  The 
neck  of  the  vase  being  smaller  than  its  base  the 
metal  must  be  compressed  to  an  unusual  degree 
as  it  is  drawn  over  toward  the  several  form-blocks. 
After  this  compression  comes  a  drawing-out  process, 
the  result  of  which  is  the  neck  of  the  vase.  Such 
severe  treatment  of  the  metal  is  safe  only  in  the 
hands  of  spinners  of  some  experience. 

In  order  to  draw  the  form-block  out  of  the  vase- 
form  after  it  is  spun,  some  kind  of  split-chuck  must 
be  used,  such  as  is  shown  at  C,  or  else  the  solid 
chuck  must  be  burned  and  bored  out  of  the  finished 
article.  As  this  last  operation  is  much  more  difficult 
than  one  might  at  first  suppose,  and,  also,  as  by  this 
method  of  ridding  the  vase  from  its  form  the  vase 
is  liable  to  be  damaged,  it  has  become  customary  to 
devise  some  form  of  split-chuck  with  a  key  piece 
which,  when  withdrawn,  will  allow  the  remainder 
of  the  chuck  parts  to  loosen,  when  they  may  be  re- 
moved with  ease. 

In  preparing  these  split-chucks  one  should  first 


58  METAL  SPINNING 

carefully  select  a  piece  of  dogwood  or  a  very 
straight-grained  piece  of  hard  maple,  and  bore  a 
hole,  with  the  grain,  through  the  block  from  end  to 
end.  It  is  desirable  that  this  hole  should  taper 
slightly.  This  may  be  accomplished  by  first  bor- 
ing a  straight  hole  and  then  carefully  gouging  it 
to  a  taper. 

A  better  method  of  tapering  the  hole  is  to  use  a 
taper  reamer  after  the  straight  hole  is  bored.  The 
reamer  will  leave  a  hole  that  will  be  true  and  con- 
sequently an  arbor  will  touch  the  stock  at  all  points. 
If  neither  of  these  methods  seems  feasible,  the 
straight,  cylindrical  hole  may  be  made  tapering  by 
using  a  tapering,  wooden  spindle  covered  with  sand- 
paper. When  the  hole  has  been  properly  prepared 
to  receive  the  spindle,  the  two  parts  of  the  chuck 
should  be  put  together  and  the  desired  form  turned. 
This  form  or  form-block,  as  we  have  called  it,  is 
next  driven  off  of  its  arbor  (the  spindle)  and  split 
as  illustrated  in  C,  Fig.  12.  The  form-block  is  split 
so  that  all  parts  taper  toward  the  center  of  the  block 
except  one,  marked  "1"  in  the  illustration.  This 
piece,  the  key  piece,  will  be  large  at  the  center  and 
small  on  the  outside  of  the  form-block.  Besides 
being  careful  in  turning  and  in  splitting  the  chuck, 
one  must  use  judgment  in  so  proportioning  all  parts 
that  the  key  piece  may  be  first  withdrawn  through 
the  hole  which  was  bored  for  the  arbor,  and  then 
others  may  be  withdrawn  without  difficulty  if  they 
are  not  left  too  thick.  When  the  chuck  has  finally 
been  prepared  as  described,  it  is  ready  for  use.  The 
parts  will  be  held  together  at  the  base  by  the  metal, 
which  has  the  same  shape  at  the  base  of  the  vase 
as  the  last  formed  chuck.  The  parts  are  held  to- 


Specimens  of  the  Spinner's  Finest  Effects 


60 


METAL  SPINNING 


METAL  SPINNING  61 

gether  at  the  top  of  the  vase  by  some  device  similar 
to  the  one  shown  at  3,  Fig.  12,  or  a  similar  device 
more  clearly  illustrated  in  Fig.  13. 

Probably  the  most  difficult  spinning  to  be  done 
in  the  vase-form  shown  in  Fig.  12  will  be  changing 
the  form  from  A  to  B.  Here  the  means  of  compres- 
sing the  metal  by  spinning  in  the  air  will  be  em- 
ployed. Bulging  ought  not  to  be  the  result,  if  the 
metal  fits  tightly  at  the  base  of  the  vase.  A  con- 
siderable amount  of  compressing  must  be  done,  how- 
ever, to  get  the  metal  into  the  cylindrical  form 
shown  in  B  and  one  must  use  a  great  deal  of  care  to 
prevent  trouble  in  this  operation.  Instead  of  keep- 
ing the  metal  as  thick  as  the  original  sheet  one  must 
compress  it  enough  (in  the  vase-forms  which  have 
a  neck)  to  allow  it  to  be  drawn  out  on  chuck  C, 
in  making  the  concavity  for  the  neck.  This  requires 
simply  that  the  process  of  compression  should  be 
continued  longer  than  usual.  The  neck  is'  formed 
by  placing  the  tool  point  under  the  axis  of  revolu- 
tion and  working  from  the  larger  diameters  toward 
the  smaller  diameters  after  the  cylindrical  form 
spun  on  B  is  placed  on  block  C.  Attention  is  called 
to  the  fact  that  the  diameters  at  3  in  B  and  C  are 
the  same,  and  also  the  same  as  the  diameter  at  2. 
Another  method  for  forming  the  neck  is  to  use  such  a 
tool  as  the  lifter;  it  is  pushed  toward  the  axis  and 
worked  downward  from  each  side  toward  the  small 
diameter. 

Should  a  form  be  desired  with  a  substantial  roll 
at  the  top,  as  in  Fig.  14,  an  additional  chuck  may 
be  required  which  will  allow  the  whole  vase,  with 
the  exception  of  the  top,  to  be  admitted,  as  shown 
in  Fig.  14  at  the  bottom  of  the  sheet.  In  this  kind 


62  METAL  SPINNING 

of  a  vase-form,  in  which  the  base  is  larger  than  the 
top,  the  chuck  used  in  making  the  rolled  neck  must 
be  split  in  halves  or  quarters  in  order  to  allow  the 
chuck  to  be  withdrawn  from  the  finished  vase-form. 

I  have  only  indicated  the  methods  employed  by 
old  spinners  in  obtaining  double-curve  vase-forms. 
There  is  great  opportunity  for  original  devices  and 
methods  in  spinning  any  article,  but  in  this  class 
of  work  perhaps  there  is  more  chance  for  the  de- 
velopment of  individuality  on  the  part  of  the  work- 
man than  in  work  such  as  has  been  described  in 
previous  chapters. 

Little  more  need  be  said  concerning  the  use  of 
tools,  annealing,  etc.  than  has  already  been  said. 
Annealing  must  take  place  whenever  necessary,  but 
workmen  should  be  proficient  enough  in  spinning, 
when  undertaking  a  difficult  form,  to  require  the 
minimum  number  of  annealings  for  a  particular 
piece  of  work.  The  tools  used  for  any  form  should 
be  selected  with  reference  to  their  size  and  shape. 
As  a  rule  the  round-nose  is  considered  the  general 
tool.  The  knob  raiser  is  the  tool  used  particularly 
for  lifting  or  raising  in  shallow  portions  of  the  form 
or  in  grooves.  The  planisher  or  the  tongue  is  a 
satisfactory  tool  for  smoothing  straight,  conical  or 
cvlindrical  surfaces. 


CHAPTER  VII 

HOW  TO  SPIN  SOME  UNCLASSIFIED 
FORMS 

^'hatever  a  man's  occupation  may  be  he  is  at 
any  time  liable  to  be  confronted  with  new  problems. 
The  school  cannot  teach  all,  even  though  it  strives 
to  lay  the  foundation  for  all.  I  have  attempted  in 
these  chapters  to  give  the  foundation  for  all  metal 
spinning  as  it  is  now  practised.  In  this  chapter  I 
shall  speak  only  of  a  few  operations  which  may  add 
to  the  information  thus  far  given,  and,  should  the 
reader  spin  other  forms  than  those  previously  de- 
scribed, this  chapter  may  be  helpful. 

Spinning  in  the  air  has  been  referred  to  as  the 
control  of  the  metal  when  it  is  spinning  between 
the  tool  in  the  right  hand  and  a  stick  in  the  left. 
It  is  true  that  this  is  one  kind  of  spinning  in  the  air, 
but  there  is  another  kind  that  I  wish  to  describe. 
In  general,  air  spinning  or  spinning  in  the  air  is  any 
spinning  operation  in  which  the  desired  form  is  ob- 
tained without  the  use  of  a  form-block  or  chuck. 
Usually  this  kind  of  spinning  requires  great  skill, 
but  there  are  operations  in  this  class  which,  with 
little  practice,  are  performed  with  comparative  ease. 
The  illustration,  Fig.  15,  shows  a  piece  of  spindle 
spinning  which  has  an  irregular  shape  in  the  center 
where  the  diameters  are  smaller  than  those  at  the 
ends  of  the  spindle.  If  all  of  this  should  be  spun 
over  a  solid  form,  it  would  be  impossible  to  with- 
draw the  form  when  spinning  was  completed.  It 
is  also  practically  impossible  to  make  a  workable 


64 


METAL  SPINNING 


in 


METAL  SPINNING  65 

split  form,  due  to  the  small  diameters.  Either  one 
of  the  following  two  methods  seems  possible.  One, 
that  of  spinning  over  a  solid  form  which  will,  in  the 
end,  be  burned  or  bored  out,  or,  the  other,  that  of 
spinning  the  metal  without  the  use  of  a  definite 
form.  The  former  of  these  two  methods  is  slow, 
and  dangerous  to  the  article  spun.  The  latter  is 
quickly  accomplished  and,  when  the  spinning  opera- 
tions are  completed,  additional  work  is  unnecessary. 

Figure  15  shows  two  chucks  used  in  forming  the 
spindle.  A  is  solid  and  is  the  form  first  used.  B 
shows  the  second  form  used.  It  will  be  noticed 
that  the  shape  of  the  chuck  A  permits  of  its  removal 
from  the  spun  article  without  difficulty.  The  shape 
of  the  finished  piece,  however,  would  interfere  in 
such  a  removal,  consequently  some  chuck  is  devised 
which  will  hold  the  metal  spindle  at  each  end  and 
may  be  withdrawn  when  the  central  part  of  the 
spindle  is  finished. 

The  part  of  the  spindle  between  points  1  and  2 
is  spun  in  the  air.  The  tool  is  carefully  pressed 
against  the  metal  as  it  revolves,  working  from  the 
large  diameter  which  was  formed  on  chuck  A  to 
the  small  diameters  as  indicated  in  the  drawing. 
Here  one  can  use  such  tools  as  the  groover  and 
tongue  to  good  advantage.  This  illustration  of  spin- 
ning in  the  air  will  serve  to  explain  the  meaning 
of  this  expression  and  to  show  the  possibilities  in 
this  direction.  The  scope  of  this  particular  kind 
of  spinning  can  only  be  realized  as  one  practises  and 
strives  to  be  ingenious  in  the  invention  of  means 
whereby  difficult  forms  may  be  produced. 

Thus  far,  with  the  exception  of  a  single  mention 
of  a  means  of  producing  a  large  roll  at  the  top  of 


66 


METAL  SPINNING 


METAL  SPINNING  67 

a  vase,  all  faceplate  chucks  described  have  been 
convex  toward  the  faceplate.  Some  work  requires 
a  chuck  which  is  concave  toward  the  head  of  the 
lathe.  Usually,  when  this  is  true,  a  preliminary 
chuck  of  the  first  kind  is  used  to  spin  the  base  of 
the  article  desired  and  also  to  spin  the  metal  above 
the  base  into  a  cylindrical  shape. 

An  example  of  work  which  will  require  both  the 
convex  and  concave  chucks  is  given  in  a  hanging 
flower  pot,  Fig.  16.  Most  plants  which  may  be 
kept  in  a  hanging  pot  require  considerable  water 
and  many  of  them  require  water  continually  stand- 
ing in  the  pot.  At  the  same  time  earth  ventilation 
is  necessary.  The  spun  pot  illustrated  on  page  66 
is  designed  to  fill  these  needs,  and  serves  in  this 
instance  as  a  good  example  for  a  problem  in  spin- 
ning. 

The  style  of  chuck  ordinarily  used  for  spinning 
cups  will  first  be  employed.  The  end  of  this  form 
is  flat  and  as  the  metal  which  will  form  the  bottom 
of  the  pot  will  be  concave,  as  illustrated,  consider- 
able metal  should  be  compressed  near  the  axis  of 
revolution  for  this  purpose.  Usually  the  first  move- 
ment of  the  tool  is  outward  from  the  center.  This 
operation  produces  a  contact  surface  and  thins  the. 
metal  slightly.  To  compress  the  metal  we  must 
move  the  tool  toward  the  center,  but  this  will  pos- 
sibly loosen  the  metal  at  the  base  and  may  also 
bulge  it.  These  risks  must  be  taken,  however,  and 
can  be  overcome  by  using  both  the  outward  and 
inward  motions  of  the  tool  in  successive  strokes. 
The  outward  strokes  will  tend  to  keep  the  metal  in 
its  proper  shape,  while  the  inward  strokes,  if  suffi- 
cient force  is  exerted,  will  compress  the  metal  slight- 


68 


METAL  SPINNING 


METAL  SPINNING  69 

ly  with  each  movement.  When  sufficient  compres- 
sion has  been  obtained,  the  metal  may  be  drawn 
over  the  chuck  as  described  in  previous  chapters. 

The  chuck  with  the  concave  bottom  is  used  when 
the  metal  has  been  spun  to  the  first  form.  The 
basket  as  it  comes  from  chuck  1  has  a  large  contact 
surface  prepared  for  chuck  2,  and  if  the  contact  is 
a  good  one,  the  center  may  here  be  dispensed  with 
and  the  rest  may  be  placed  at  right  angles  to  the 
lathe-bed  and  directly  in  front  of  the  work  after  the 
neck  of  the  basket  is  spun.  The  raising-up  tool, 
round-nose  or  knob  raiser  may  be  employed  in  con- 
caving the  bottom  by  gradually  working  the  tool 
outward,  principally,  and  inward  but  slightly.  The 
hole  in  the  bottom  can  be  drilled  through  while  the 
work  is  still  on  the  chuck,  by  placing  a  drill  in  a 
tailstock  chuck  as  in  regular  machine-shop  work. 
Probably  the  hole  may  be  as  satisfactorily  cut  by 
using  the  point  of  a  diamond  point  hand-tool  just 
before  removing  the  basket  from  this  chuck  or  form- 
block,  which  must  be  split  as  in  Fig.  14,  as  by 
drilling. 

I  believe  we  have  considered  all  the  necessary 
operations  for  spinning  single  pieces  of  metal.  I 
shall  attempt  to  give  the  reader  an  idea  of  the 
method  of  spinning  two  pieces  of  metal  together. 
No  better  example,  I  believe,  can  be  given  than 
the  hollow  sphere.  Illustrations  of  this  are  shown  in 
Fig.  17. 

Two  hemispheres  are  separately  spun  as  illus- 
trated at  A.  In  fact  each  should  be  greater  in  depth 
than  in  diameter  to  allow  for  the  inward  and  out- 
ward turns  of  the  edges  shown  at  B.  After  the  two 
pieces  have  come  from  the  convex  chuck,  each  is 


70 


METAL  SPINNING 


METAL  SPINNING  71 

put  into  a  concave  chuck  which  permits  the  hemi- 
spheres to  set  inside  with  the  amount,  which  was 
left  for  the  turn,  projecting.  The  outward  turn  is 
easily  made  by  gently  pressing  the  round-nose  or 
the  back  of  the  tongue  tool  against  the  edge  of  the 
metal  on  the  inside  of  the  hemisphere  and  allowing 
the  tool  to  follow  the  metal  as  it  rolls  outward. 
After  the  roll  has  been  made  it  may  be  pressed 
down  to  the  regular  shape  and  thickness. 

The  half  which  has  the  edge  turned  inward  is 
placed  in  the  same  chuck  which  was  used  for  the 
first  half  and  the  turn  accomplished  in  practically 
the  same  manner,  except  that  the  tool  is  pressed 
against  the  metal  from  the  outside  and  follows  it 
as  it  turns  inward.  When  the  turn  has  been  com- 
pleted to  the  satisfaction  of  the  workman,  he  presses 
the  end  of  the  grooving  tool  or  round-nose  against 
the  inside  of  the  hemisphere  just  at  the  end  of  the 
turn  and  makes  the  slight  roll  shown  at  B. 
This  forms  a  slight  shoulder  against  which  the 
second  half  of  the  sphere  presses  when  the  two  are 
formed  together.  Either  the  inward  or  outward 
rolled  edge  may  be  formed  by  the  use  of  the  spin- 
ners' pliers  which  are  shown  in  Fig.  18.  If  these 
are  employed  instead  of  the  ordinary  spinning  tools, 
they  grasp  the  edge  of  the  metal  as  it  revolves  and 
the  workman  throws  the  handle  in  or  out,  depending 
upon  the  formation  of  the  inward  or  outward  turn. 
It  is  best  to  complete  last  the  half  having  the  in- 
ward roll.  This  half  should  remain  in  the  chuck 
when  the  two  halves  are  formed  together. 

Leaving  the  first  half  in  its  place  in  the  chuck, 
the  second  half  is  pressed  into  it  until  the  two  rolls 
come  together,  when  the  tail  center  is  drawn  up 


72  METAL  SPINNING 

and  presses  the  two  halves  firmly  together.  A  firm 
but  slight  pressure  with  the  end  of  the  groover  spins 
the  two  halves  together.  If  the  sphere  is  desired 
perfectly  air  or  water  tight,  a  bit  of  solder  may  be 
run  into  the  seam. 

The  method  of  making  the  sphere  just  described 
is  by  no  means  a  simple  one  nor  is  it  one  that  can 
be  followed  with  success  by  all  workmen.  C  in 
Fig.  17  shows  another  means  of  reaching  the  same 
results  in  an  easier  way,  but  here  an  extra  strip  is 
soldered  on  the  inside  of  one  of  the  hemispheres 
which  does  not  permit  of  spinning  operations  alone 
being  used  in  the  production  of  the  finished  article. 
Such  a  problem  as  this  is  more  practically  done  by 
pressing  machines  than  by  spinning  methods  as 
herein  described. 

In  closing  this  chapter,  and  as  a  last  word,  I  wish 
to  express  the  hope  that  many  will  undertake  this 
almost  entrancing  form  of  cold  metal  work.  It  de- 
serves a  place  among  the  crafts,  and,  I  believe,  is 
worthy  of  consideration  from  a  commercial  stand- 
point. 


Examples  in  Copper 


Contents 

Aluminum „     ....  37 

Brass 36 

Copper 32 

Dish,  Deep,  How  to  Spin 49 

Dish,  Shallow,  How  to  Spin       ....  39 

Lathe  and  Its  Parts 11 

Metal,  Preparation  for  Spinning       ...  31 

Metal,  White 35 

Preparation  of  Metal  for  Spinning   ...  3 1 

Tools. .     .  21 

Unclassified  Forms,  How  to  Spin    ...  63 

Vase,  How  to  Spin 55 

White  Metal 35 

Zinc    .  37 


University  of  California 

SOUTHERN  REGIONAL  LIBRARY  FACILITY 

305  De  Neve  Drive  -  Parking  Lot  17  •  Box  951388 

LOS  ANGELES,  CALIFORNIA  90095-1388 
Return  this  material  to  the  library  from  which  it  was  borrowed. 


Form  L-9-15»n-2,'36 


LIBRARY 


A     000  503  352     7 


- 


TT 


CALIFORNIA 

:GELES 
ry 


